1. Field of the Invention
The present invention relates to a washing machine, and more particularly, to a method of sensing a current laundry amount during a wash cycle of a washing machine.
2. Discussion of the Related Art
In a typical washing machine, a user puts laundry in a tub via a door, applies power to the machine, inputs a washing command, and starts a wash cycle of a wash course. Then, a controller controls a load driver according to the washing command input and other factors, such as a sensed amount of laundry.
Referring to FIG. 1, a washing machine according to a related art is comprised of a key input unit 1 for inputting a user command, a voltage sensing unit 2 for outputting a voltage signal in accordance with a sensed amount of laundry, a controller 3 for outputting a control signal for controlling steps of the washing machine once a start button of the key input unit has been pressed, a load driver 4 for driving a motor, valves, and the like (not shown) according to the control signal of the controller. The voltage signal output of the voltage sensing unit 2 is a number of pulses proportional to the amount of laundry in the tub. The pulses are input to the controller 3, which counts the number of the pulses to determine the laundry amount and a corresponding water level.
Referring to FIG. 2, illustrating an operating method of the above washing machine, the washing machine is powered-on in a step S1. With laundry loaded into the washing machine, a user selects a wash course in a step S2 and then starts the operation in a step S3. Thereafter, prior to the tub filing with water, the amount of dry laundry in the tub is sensed in a step S4. Subsequently, in a step S5, water is supplied according to the sensed laundry amount. Finally, after a predetermined water level is reached, washing is performed in a step S6 according to the sensed laundry amount. The washing step typically includes a predetermined cycle of washing, rinsing, and dewatering performed according to the user command input via the key input unit 1 and controlled by the controller 3.
Notably, there may be instances where the user decides, shortly after the wash cycle begins and during the washing, to include additional laundry with the original amount of laundry that was sensed to determine the wash cycle performance. In the washing machine of the related art as described above, however, if additional laundry is put in the washing machine during the wash cycle, i.e., with the water level set according to the sensed laundry amount, the additional laundry cannot be detected, and the water supply is thus inappropriate. To add laundry into the above washing machine shortly after the initiation of a wash course, the proceeding wash course should be ended and a new wash course initiated, so that a selected wash course is appropriately performed according to the new laundry amount. Otherwise, the water supply for the additional laundry is improper.